Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisors: John L. Gallagher, and Denise M. Seliskar, School of Marine Science & Policy.. Includes bibliographical references.

Thesis (M.S.)--Baylor University, 2006. / Includes bibliographical references (p. 73-78).

The aims of this dissertation are to better understand the sources of aerosol particles reaching coastal Antarctica, and the processes that control aerosol deposition to the snow surface and inclusion into the ice. Daily collections of aerosol particles and surface snow samples were made from British Antarctic Survey base, Halley. Aerosol and snow sea salt were found to have maximum concentrations during the austral winter and non sea salt sulphate and methane sulphonic acid concentrations peaked during the summer, confirming previous work by other authors. These species were compared with local meterological events (such as wind speed and direction) to identify a source for particularly high concentration events. Winter sea salt was found to have a local source, consisting probably of concentrated brine pools on surfaces of freshly formed sea ice and needle-like structures, known as frost flowers, which form from the pools. The sea salt component of these high events was also found to be fractionated, with a deficit of sodium sulphate (mirabilite). Methane sulphonic acid and nonsea salt sulphate did not appear to have a local source. Instead, using back trajectories of air mass origins to identify a longer range aerosol source, high concentration events were associated with the air mass having passed over an area of open water several days before reaching Halley. The processes of aerosol deposition to the snow surface were then quantified. Dry, fog and wet deposition, sublimation, wind pumping, blowing and drifting snow were examined experimentally and theoretically. For this coastal Antarctic location, wet deposition was found to be highly dominant (80%). Dry deposition accounted for about 10% and drifting and blowing snow were found to be important in determining whether a snowfall event remained recorded in the accumulated snow record, and ultimately in any ice core. This thesis has suggested that for sea salt, methane sulphonic acid (MSA) and non sea salt sulphate, there may be an alternate way of interpreting concentrations of these species in coastal Antarctic ice cores. Rather than an indication of increased storminess and long range transport, high loadings of sea salt could actually give information on the extent of new, fresh sea ice and could therefore be used to infer the local temperature, sea ice extent and possible wind direction at the time of core formation. Elevated MSA and non sea salt sulphate concentrations in ice cores could also give us information on the extent of open water and not simply an increase in marine biogenic activity and DMS emissions.

abstract: Coal bed natural gas (CBNG) production has become a significant contribution to the nation's energy supply. Large volumes of water are generated as a byproduct of CBNG extraction, of which this "product water" is relatively high in sodium. High sodicity reduces water quality and limits environmentally compliant disposal options for producers. Crop irrigation with CBNG product water complies with state and federal laws and is a disposal method that also provides a beneficial use to private landowners. However, this disposal method typically requires gypsum and sulfur soil amendments due to the high levels of sodium in the water, which can reduce soil infiltration and hydraulic conductivity. In this study, I tested a new product called Salt Extractor that was marketed to CBNG producers to ameliorate the negative effects of high sodicity. The experiment was conducted in the Powder River Basin of Wyoming. I used a random block design to compare the soil and vegetation properties of plots following application with CBNG product water and treatments of either Salt Extractor, gypsum and sulfur (conventional), or no treatment (control). Data was analyzed by comparing the amount of change between treatments after watering. Results demonstrated the known ability of gypsum and sulfur to lower the relative sodicity of the soil. Plots treated with Salt Extractor, however, did not improve relative levels of sodicity and exhibited no favorable benefits to vegetation. / Dissertation/Thesis / M.S. Biology 2011

Hypertension is both a domestic and international health issue – diagnosed in 1 in 3 U.S. adults and classified by the World Health Organization as the number one risk factor for mortality worldwide. It has been established that salt plays a role in the development of hypertension, and that a salt-sensitive phenotype indicates heightened sensitivity to salt consumption. Here, we studied the roles of the afferent renal nerves, which travel from the kidney to the central nervous system, and the sodium-chloride cotransporter in fluid and electrolyte homeostasis and blood pressure regulation. Our laboratory utilized a novel technique of afferent renal nerve ablation on Sprague-Dawley rats to examine the effects of afferent renal nerve mechanoreceptors and chemoreceptors in response to acute sympathoinhibitory challenges. Additionally, salt-sensitive and salt-resistant rats were randomly subjected to chronic normal salt (0.6% NaCl) or high salt (8% NaCl) diets, and examined for levels of norepinephrine and substance-P release. A different group of salt-resistant and salt-sensitive rats were subcutaneously infused with terazosin, a selective -1 adrenoreceptor antagonist, or propranolol, a selective -adrenoreceptor antagonist, and then randomly subjected to normal salt (0.6% NaCl) or high salt (4% NaCl) diets for 21 days. We subsequently examined these rats, and analyzed the effects of high salt intake on blood pressure, sodium-chloride cotransporter activity, and expression of the sodium-chloride cotransporter and its relevant kinases. In response to an acute mechanoreceptor-specific stimulus, Sprague-Dawley rats that underwent afferent renal nerve ablation were unable to modulate blood pressure or natriuresis after regaining consciousness. Chronic high salt (8% NaCl) consumption in salt-sensitive rats resulted in increased levels of plasma norepinephrine, renal norepinephrine, and norepinephrine-evoked Substance-P release. In addition, salt-sensitive rats subjected to a 21-day high salt (4% NaCl) diet exhibited increased blood pressure, elevated sodium-chloride cotransporter activity, and upregulated levels of the sodium-chloride cotransporter and the kinases that regulate it. However, these observed increases in blood pressure, protein activity, and protein expression were abolished in salt-sensitive rats experiencing -1 adrenoreceptor antagonism due to terazosin administration. In conclusion, our findings indicate that mechanoreceptor-driven afferent renal nerve activation is needed to maintain fluid and electrolyte homeostasis and regulate blood pressure in response to acute sympathoinhibitory challenges and chronic high salt intake. In addition, our data demonstrates that the sodium-chloride cotransporter is aberrantly upregulated in salt-sensitive rats through a norepinephrine-1-adrenoreceptor gated pathway, and this this upregulation results in excessive salt reabsorption. Thus, our experiments have generated new data that reveals selective 1-adrenoreceptor antagonism and renal denervation as potential treatment options for hypertensive individuals.

abstract: Stable isotopes were measured in the groundwaters of the Salt River Valley basin in central Arizona to explore the utility of stable isotopes for sourcing recharge waters and engineering better well designs. Delta values for the sampled groundwaters range from -7.6‰ to -10‰ in 18O and -60‰ to -91‰ in D and display displacements off the global meteoric water line indicative of surficial evaporation during river transport into the area. Groundwater in the basin is all derived from top-down river recharge; there is no evidence of ancient playa waters even in the playa deposits. The Salt and Verde Rivers are the dominant source of groundwater for the East Salt River valley- the Agua Fria River also contributes significantly to the West Salt River Valley. Groundwater isotopic compositions are generally more depleted in 18O and D with depth, indicating past recharge in cooler climates, and vary within subsurface aquifer layers as sampled during well drilling. When isotopic data were evaluated together with geologic and chemical analyses and compared with data from the final well production water it was often possible to identify: 1) which horizons are the primary producers of groundwater flow and how that might change with time, 2) the chemical exchange of cations and anions via water-rock interaction during top-down mixing of recharge water with older waters, 3) how much well production might be lost if arsenic-contributing horizons were sealed off, and 4) the extent to which replacement wells tap different subsurface water sources. In addition to identifying sources of recharge, stable isotopes offer a new and powerful approach for engineering better and more productive water wells. / M.S. Geological Sciences 2010

The present study aimed to examine the effects of root colonization in tomato, Solanum lycopersicum L. cv. Moneymaker, by the arbuscular mycorrhizal (AM) fungus, Glomus intraradices Shenck and Smith, on alleviating salt stress. I postulated that AM symbiosis increases tomato plant performance to salt stress. Two greenhouse experiments were done according to a randomized factorial experimental design. The results showed a significantly higher level of AM root colonization that also occurred earlier in salt than non-salt treated plants. There were also positive interactions between root colonization levels and the alleviation of salt stress; these contributions resulted initially on higher root fresh mass (FM), later on shoot FM, and DM, and higher phosphorus and unchanged potassium concentrations in roots. The effects observed in salt-treated plants were significant when root colonization levels were significantly different than those observed in non-salt treated plants. This suggests a relationship between the level of root colonization and the alleviation of salt stress in plants. The attempt to use molecular techniques to detect early root colonization was quite successful in detecting the presence of G. intraradices in AM plants. However, it was not possible to detect the presence of the AM fungus as early as by classical root staining. This was observed presumably because sampling methods were different. In general, the results support the hypothesis that AM root colonization contributes to some extent to salt resistance of tomato plants.

Crude oil leakages often give rise to in situ contamination with both oil and salt. In this study, the biodegradation of model alkanes and of saturated hydrocarbons in whole crude oil by hydrocarbon-degrading bacteria was investigated at different salt (NaCl, KCl, Na2SO4) concentrations. Changes in cell surface hydrophobicity at different NaCl concentrations were also investigated. The results show that with increasing NaCl concentration, the lag phase for strain growth on hydrocarbons was prolonged; however, the total degradation efficiency was not influenced greatly. The formation of different sizes of cell aggregates at different salt concentrations indicated that salt could indirectly influence mass transfer of hydrocarbons from the medium to the interior of the cells. The results also showed that KCl had a less inhibitory effect on biodegradation than NaCl, and changes of Na2SO4 concentration did not greatly affect biodegradation. In addition, cell surface hydrophobicity increased with increasing NaCl concentration when the cultures were grown on hydrocarbons.

The role of natural earth licks in the ecology of the mountain goat (Oreamnos americanus (Blainville)) was studied during the summers of 1965 and 1966 in the Rocky Mountain Trench of southern B.C. The patterns of movements of the animals were determined as they used the licks and the vegetation, lick soils and blood serum were analyzed with respect to sodium content. The predicated use of licks as suggested by other workers involves the idea that sodium may be the attracting element. The present study examined seasonal and differential patterns of movement, along with periodicity of use, in order to determine the resultant interplay of animal movement and sodium and water content of the vegetation. The goat encounters such additional risks as predation, parasitism, hunting and joint use while using the lick seasonally. Since the goats use the lick differentially in time, each sex is affected to a different degree by the above factors. Differential use also produces characteristic patterns of grouping and molting. Periodicity of use occurred mainly in the afternoon, although distance travelled and complexity of the lick may affect time of entry, length of stay and group size. The frequency of use differed at each lick, with the average time of use by an individual being one to three weeks. Environmental factors such as temperature and weather appear to regulate the movement to and from the lick. Analysis of the vegetation revealed that sodium was extremely low and that potassium was present in sufficient quantities to meet the requirements of the animal. No significant trends were found to exist from spring to fall or due to changes in elevation, as far as sodium and total ash were concerned. Observations indicated that animals select certain licks over others and select sites within a lick. These high licking sites were shown to have a higher sodium content. Newly established licks had a higher sodium content than did old licks, however, highly preferred sites were not always higher in calcium, phosphorus or cobalt. A normal range of serum sodium values was established for the goat but due to the regulatory function of the kidney, changes in serum sodium due to lick use could not be detected. Serum sodium decreased with age. A female with a kid had a low serum value. It appears that the level of deficiency causing the craving is not sufficient to show up in serum analysis. Animals died during trapping operations and a selenium deficiency was suspected. Gross symptoms approximated those attributed to white muscle disease and the vegetation contained selenium in amounts which are known to cause this myopathy. / Science, Faculty of / Zoology, Department of / Graduate

Spores from a weakly salt tolerant strain of Ceratopteris richardii containing the mutation stl1 were irradiated and sown on nutrient medium supplemented with 200 m M NaCl. A single highly salt tolerant gametophyte was recovered and selfed to generate a homozygous sporophyte. Spores from this strain, 10α23, were used to document the sexual transmission of the trait and to monitor the inheritance of tolerance in crosses to both the wild type and to the parental salt tolerant strain. Genetic analysis showed the 10α23 strain to possess both the original stl1 mutation and an additional semi-dominant nuclear mutation, stl2, that individually conferred a high level of tolerance to gametophytes. In combination, both mutations had additive effects. Tolerance was also evident in sporophytes, but at a lower level than in gametophytes.